Browsing by Author "Su, Hui"
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Item Five year (2004–2009) observations of upper tropospheric water vapor and cloud ice from MLS and comparisons with GEOS-5 analyses(AGU, 2010-08-03) Jiang, Jonathan H.; Su, Hui; Pawson, Steven; Liu, Hui-Chun; Read, William G.; Waters, Joe W.; Santee, Michelle L.; Wu, Dong L.; Schwartz, Michael J.; Livesey, Nathaniel J.; Lambert, Alyn; Fuller, Ryan A.; Lee, Jae N.This paper gives an overview of August 2004 through February 2010 upper tropospheric (UT) water vapor (H₂O) and ice water content (IWC) from the Aura Microwave Limb Sounder (MLS) and comparisons with outputs from the NASA Goddard Earth Observing System Version 5 (GEOS-5) data assimilation system. Both MLS and GEOS-5 show that high values of H₂O and IWC at 215 to 147 hPa are associated with areas of deep convection. They exhibit good (within ∼15%) agreement in IWC at these altitudes, but GEOS-5 H₂O is ∼50% (215 hPa) to ∼30% (147 hPa) larger than MLS values, possibly due to higher temperatures in the data assimilation system at these altitudes. A seasonally migrating band of tropical deep convection is clearly evident in both the MLS and GEOS-5 UT H₂O and IWC, but GEOS-5 produces a weaker intertropical convergence zone than MLS. MLS and GEOS-5 both show spatial anticorrelation between IWC and H₂O at 100 hPa, where low H₂O is associated with low temperatures in regions of tropical convection. At 100 hPa, GEOS-5 produces 50% less IWC and 15% less H₂O in the tropics, and ∼20% more H₂O in the extratropics, than does MLS. Behavior of the 100 hPa H₂O is consistent with it being controlled by temperature. The seasonal cycle in the vertical transport of tropical mean H₂O from ∼147 hPa to ∼10 hPa appears much stronger in MLS than in GEOS-5. The UT IWC and H₂O interannual variations, from both MLS and GEOS-5, show clear imprints of the El Niño–Southern Oscillation.Item Using Deep Space Climate Observatory Measurements to Study the Earth as an Exoplanet(IOP, 2018-06-27) Jiang, Jonathan H.; Zhai, Albert J.; Herman, Jay; Zhai, Chengxing; Hu, Renyu; Su, Hui; Natraj, Vijay; Li, Jiazheng; Xu, Feng; Yung, Yuk L.Even though it was not designed as an exoplanetary research mission, the Deep Space Climate Observatory (DSCOVR) has been opportunistically used for a novel experiment in which Earth serves as a proxy exoplanet. More than 2 yr of DSCOVR Earth images were employed to produce time series of multiwavelength, single-point light sources in order to extract information on planetary rotation, cloud patterns, surface type, and orbit around the Sun. In what follows, we assume that these properties of the Earth are unknown and instead attempt to derive them from first principles. These conclusions are then compared with known data about our planet. We also used the DSCOVR data to simulate phaseangle changes, as well as the minimum data collection rate needed to determine the rotation period of an exoplanet. This innovative method of using the time evolution of a multiwavelength, reflected single-point light source can be deployed for retrieving a range of intrinsic properties of an exoplanet around a distant star.